1. Field of the Invention
The present invention relates to a transformer having a high degree of coupling in which inductance elements are coupled to each other with a high degree of coupling and an electronic circuit and an electronic device that include the transformer having a high degree of coupling.
2. Description of the Related Art
Transformers generally include primary coils and secondary coils that are magnetically coupled to each other via magnetic paths. The transformers are widely used in various electronic circuits and electronic devices, such as voltage step-up and step-down circuits, transformers having a high degree of coupling, current transformation and shunt circuits, balance-unbalance conversion circuits, and signal transmission circuits.
In order to reduce the loss in transmission energy in the transformers, it is necessary to increase the degree of coupling between the primary coils and the secondary coils. For this purpose, methods of winding the primary coils and the secondary coils around ferrite magnetic bodies commonly used for the primary coils and the secondary coils have been adopted, for example, as described in Japanese Unexamined Patent Application Publication No. 10-294218 and Japanese Unexamined Patent Application Publication No. 2002-203721.
However, since lead wires are wound around the ferrite magnetic bodies to form the coils in the transformers disclosed in Japanese Unexamined Patent Application Publication No. 10-294218 and Japanese Unexamined Patent Application Publication No. 2002-203721, the manufacturing processes are complicated and the transformers are increased in size.